Chinese coast guard ships were spotted Wednesday for the first time near disputed islands controlled by Japan following a reorganisation of the service to boost Beijing’s ability to enforce its maritime claims.

Japan’s coast guard said four Chinese craft were seen early in the day just outside Japanese territorial waters around the tiny uninhabited East China Sea islands called Diaoyu by China and Senkaku by Japan.

Chinese websites ran photos reportedly taken by the Japanese coast guard showing a ship painted in the service’s new red, white and blue striped Chinese coast guard livery.

The reorganised service, which was formally inaugurated on Monday, merges the coast guard with four agencies responsible for fisheries administration, maritime surveillance, customs enforcement and border control. Chinese officials said the move would help boost efficiency in law enforcement and “better safeguard China’s sovereignty and maritime rights and interests.”

The new service is being equipped with ships from the four bodies being eliminated, along with newly built or repurposed craft that could make it Asia’s biggest and most powerful coast guard. The ships are believed to be lightly armed with machine guns and possibly cannons, giving them teeth to back China’s claims to seas and islands if Beijing wished to do so.

The Japanese coast guard said the Chinese vessels were apparently taking the place of ships from China Marine Surveillance, one of the bodies being absorbed by the new service. Those ships had been patrolling in the area for the past eight days as part of a regular Chinese presence in the area, the Japanese coast guard said.

Since an escalation of tensions over the islands, Japanese and Chinese patrol craft have confronted each other on a regular basis in the waters surrounding them, although no clashes have been reported.

China has also frequently sparred with the Philippines and Vietnam over overlapping claims to parts of the South China Sea, another area to which the new coast guard is being deployed.